本节主要就merge和dplyr::*_join函数做出解释。...包中的inner_join、left_join、right_join、full_join语法
inner_join(x, y, by = NULL, copy = FALSE, suffix = c("...suffix = c(".x", ".y"), ...)
right_join(x, y, by = NULL, copy = FALSE, suffix = c(".x", ".y"),
...)
full_join...::full_join(……)所有数据均加入,如无法连接则生成NA
> #外连接
> merge(student1,student2,by="ID",all=TRUE)
ID name score...1 1 Jim 89
2 2 Tony 22
3 3 Lisa NA
4 5 78
> dplyr::full_join(student1,student2,